The correct answer is 21 simply because 21 is a multiple of 3 and a multiple of 7, other answer does not hold this conclusion.
The answer to the problem is A) 20 feet below sea level
The answer is 9.2, because when the number behind the number being rounded is 5 or above, you round up. if the number was 9.14, it would be rounded down to 9.1 :)
